JP7184542B2 - Chemical mechanical polishing pad for improved removal rate and planarization - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser.

The present invention relates to chemical mechanical polishing pads and methods of use thereof. In particular, the present invention relates to 4,4′-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA), or MCDEA and 4,4′-methylene-bis-o-(2-chloroaniline) (MbOCA). ) and a polyol of polytetramethylene ether glycol (PTMEG), polypropylene glycol (PPG), or a polyol blend of PTMEG and PPG, and an aromatic diisocyanate, or an aromatic diisocyanate and a cycloaliphatic A polishing layer of a polyurethane reaction product of a thermosetting reaction mixture comprising a polyisocyanate prepolymer containing 8.6-11% by weight of unreacted isocyanate (NCO) produced from a combination of diisocyanates; or The present invention relates to a chemical mechanical polishing pad having a low attenuation component that includes an upper polishing surface and methods of using the pad for polishing three-dimensional semiconductor or memory substrates, such as non-volatile flash memory (eg, 3D NAND) substrates.

Several chemical mechanical polishing (CMP polishing) processes may be required in the production of any semiconductor or memory device. In each CMP process, a polishing pad combined with a polishing solution, such as an abrasive-containing polishing slurry or an abrasive-free reactive liquid, removes excess material to planarize or maintain the flatness of the substrate. . Multiple layers of stacks in semiconductors combine to form integrated circuits. The manufacture of such semiconductor devices continues to become more complex due to the requirement for devices with higher operating speeds, lower leakage currents and lower power consumption.

The advent of three-dimensional memory architectures (eg, 3D-NAND) and three-dimensional stacked memory cells or arrays has necessitated CMP polishing of substrates with wide lateral dimensions. Such substrates require feature or die scale planarization with lateral dimensions, eg, 1-50 mm, between features that need to be planarized. In particular, 3D NAND memory substrates with at least one 1-5 mm wide low region have created new geometries for CMP polishing. Such geometries include significantly thicker oxides (>1 μm) and wider lateral features (1-10 mm) that require feature-scale planarization. Thick oxides impose exceptionally high removal rate requirements, and large features require new classes of CMP polishing pad materials that can planarize lateral lengths orders of magnitude greater than previous CMP substrates.

U.S. Pat. Publication No. 2015/0059254 A1 by Yeh et al. describes polypropylene glycol and toluene diisocyanate and 4,4′-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA) as a curing agent. A polyurethane polishing pad is disclosed comprising a polyurethane reaction product of a polyurethane prepolymer derived from ). The resulting CMP polishing pad allows for improved polishing of metal-containing substrates, but effectively does not remove three-dimensional semiconductor or memory substrates having an oxide layer at least 1 μm thick and at least one low region 1-5 mm wide. Does not achieve the removal rate required for polishing.

The inventors have discovered an effective chemical mechanical polish (CMP polish) that achieves the removal rates and wide-scale planarization needed to polish three-dimensional semiconductor or memory substrates, such as non-volatile flash memory (3D NAND) substrates. ) aimed at solving the problem of providing pads.

Description of the invention 1 . In the present invention, a chemical mechanical (CMP) polishing pad having a low attenuation component for polishing a substrate selected from at least one of a three-dimensional memory and a semiconductor substrate comprises 4,4′-methylenebis(3-chloro- 2,6-diethylaniline) (MCDEA) or MCDEA to 4,4′-methylene-bis-o-(2-chloroaniline) (MbOCA) weight ratio of 3:7 to 1:0 or preferably 4 : 6-1:0 mixture of MCDEA and MbOCA curing agent and 8.6-11% by weight of the polyisocyanate prepolymer, or preferably 8.6-10.3% by weight of unreacted isocyanate. toluene diisocyanate (TDI); naphthalene diisocyanate (NDI); paraphenylene diisocyanate (PPDI); or o-toluidine diisocyanate (TODI); modified diphenylmethane diisocyanates such as carbodiimide-modified diphenylmethane diisocyanate, allophanate-modified diphenylmethane diisocyanate, biuret-modified diphenylmethane diisocyanate; or MDI, preferably toluene diisocyanate (TDI) or TDI and aromatic Aromatic isocyanurates derived from diisocyanates, such as isocyanurates of mixtures of up to 20% by weight of MDI, based on the total weight of diisocyanates; or one or two aromatic diisocyanates, preferably Up to 67% by weight, or preferably up to 64.5% by weight of 4,4'-methylenebis(cyclohexylisocyanate), based on total weight of TDI or aromatic diisocyanate and optionally cycloaliphatic diisocyanate One or two aromatics, such as those selected from up to 20% by weight of MDI, based on the total weight of TDI and aromatic diisocyanates, mixed with cycloaliphatic diisocyanates such as (H ₁₂ -MDI) and a polytetramethylene ether glycol (PTMEG), polypropylene glycol (PPG) polyol, or a polyisocyanate prepolymer made from a polyol blend of PTMEG and PPG as reactants. a polishing layer adapted for polishing a substrate that is a mixture of polyurethane reaction products, the polyurethane reaction product in the polishing layer comprising A Shore D hardness (2 sec) according to STM D2240-15 (2015) of 50 to 90, or preferably 60 to 90 or 70 to 80; It has a shear storage modulus (G') of 70 to 500 MPa, or preferably 125 to 500 MPa, or preferably up to 260 MPa.

2. In the chemical mechanical polishing pad of the present invention according to item 1 above, the sum of the total number of moles of amine (NH ₂ ) groups and the total number of moles of hydroxyl (OH) groups in the reaction mixture versus unreacted isocyanate in the reaction mixture The stoichiometric ratio of total moles of nato (NCO) groups ranges from 0.85:1 to 1.20:1, or preferably from 1.00:1 to 1.10:1.

3. In the chemical mechanical polishing pad of the present invention according to item 1 or 2 above, the polyol used to produce the polyisocyanate prepolymer is (i) PTMEG, (ii) PPG or (iii) 1:0 to 1:4 or a polyol blend of PTMEG and PPG in a ratio of PTMEG to PPG of, for example, 12:1 to 1:1.

4. In the chemical mechanical polishing pad of the present invention according to any one of items 1, 2 or 3 above, the weight average molecular weight (GPC) of PTMEG in the polyol or polyol blend is 800 to 1600, or preferably 1100. ~1500.

5. The chemical mechanical polishing pad of any one of the above items 1, 2, 3 or 4, wherein the polishing layer of the CMP polishing pad comprises entrapped air bubbles, hollow core polymeric materials such as polymeric microspheres, fluid-filled Further comprising microelements selected from liquid-filled hollow core polymeric materials such as polymeric microspheres and fillers such as boron nitride, preferably expanded, fluid-filled polymeric microspheres.

6. In the chemical mechanical polishing pad of the present invention as described in item 5 above, the amount of microelements is 0.4-2.5% by weight based on the total weight of the reaction mixture, or more preferably 0.75-2. One or more microelements range from 0% by weight.

7. In the chemical mechanical polishing pad of ^the present invention according to any one of items 5 or 6 above, the polishing pad or polishing layer has a / cm ³ density.

8. The chemical mechanical polishing pad of the present invention according to any one of items 5, 6 or 7 above, wherein the polishing pad or polishing layer has a porosity of 0.01 to 53% or preferably 8 to 40%. .

9. 9. The chemical mechanical polishing pad of the present invention according to any one of items 1, 2, 3, 4, 5, 6, 7 or 8 above, wherein the polishing layer comprises from 45 to 45, based on the total weight of the thermosetting reaction mixture. It comprises a polyurethane reaction product with 70%, or preferably 50-70% hard segment.

10. In the chemical mechanical polishing pad of the present invention according to any one of items 1, 2, 3, 4, 5, 6, 7, 8 or 9 above, the polishing layer has a thickness of 0.06 to 0.13 or preferably , 0.068-0.118 with a damping component (G''/G' measured by shear dynamic mechanical analysis (DMA), ASTM D5279-08 (2008)) at 50°C.

11. In another aspect, the present invention provides a substrate selected from at least one of a magnetic substrate, an optical substrate and a semiconductor substrate; providing a polishing pad; providing an abrasive polishing medium; causing dynamic contact between the polishing surface of the polishing layer of the CMP polishing pad, the abrasive polishing medium, and the substrate at a pressure of 103-550 hPa (1.5-8 psi); ) downforce; and conditioning the polishing surface of the polishing pad with an abrasive conditioner.

12. In the method of the present invention according to item 11 above, the substrate comprises a three-dimensional semiconductor or memory substrate, for example a 3D NAND memory.

13. In the method of the present invention according to item 12 above, the three-dimensional semiconductor or memory substrate comprises an oxide film at least 1 μm thick, or preferably 1 to 7 μm thick, or more preferably 1 to 4 μm thick, and It has at least one low region that is 5 mm wide.

14. In the method of any one of items 12 or 13 above, dynamic contacting results in a removal rate of at least 8000 Å/min or preferably at least 10,000 Å/min.

15. 15. The method of any one of items 12, 13 or 14 above, wherein the dynamic contacting comprises an abrasive polishing medium, such as ceria, having a total abrasive solids content of 0.5 to 7 weight percent. and polishing with an abrasive polishing medium at a downforce of 103-550 hPa (1.5-8 psi), or preferably 206-483 hPa (3-7 psi).

16. In the method of the present invention according to item 15 above, the dynamic contact is caused by abrasive with an abrasive grain content of 0.5 to 1.999% by weight, or preferably 0.5 to 1.5% by weight. Providing a grain abrasive media and abrading with a down force of 206-550 hPa (3-8 psi), or preferably 275-483 hPa (4-7 psi).

17. 15. In the method of the present invention according to item 15 above, the dynamic contacting comprises an abrasive polishing medium having an abrasive content of 2 to 6 wt %, or preferably 2.5 to 5.5 wt %. providing and polishing with a Down Force (DF) of 103-344 hPa (1.5-5 psi) or preferably 137-344 hPa (2-5 psi).

Unless otherwise specified, temperature and pressure conditions are ambient or room temperature and standard pressure. All ranges recited are inclusive and combinable.

Unless otherwise stated, any term containing brackets alternatively refers to the entire term and the unbracketed term as if the brackets were absent, and to each alternative combination. The term "(poly)isocyanate" therefore refers to isocyanates, polyisocyanates, or mixtures thereof.

All ranges are inclusive and combinable. For example, the term "range of 50-3000 cPs, or 100 cPs or greater" would include 50-100 cPs, 50-3000 cPs and 100-3000 cPs, respectively.

As used herein, the term "ASTM" refers to a publication of ASTM International (West Conshohocken, PA).

As used herein, the terms G′, G″, and G″/G′ (which corresponds to tan δ) are shear storage modulus, shear loss modulus, and shear storage modulus, respectively. Refers to the ratio of shear loss modulus to modulus. Specimens were cut with a width of 6.5 mm and a length of 36 mm. ARES™ G2 torsional rheometer or Rheometric Scientific™ RDA3 (both from TA Instruments, New Castle, Del.) are tested using ASTM D5279-13 (2013), "Standard Test Method for Plastics: Dynamic Mechanical Properties: In Torsion ” was used according to The gap length was 20 mm. The analytical parameters of the instrument were set at a preload of 100 g, strain of 0.2%, vibration rate of 10 rad/sec, and temperature ramp rate of 3° C./min (−100° C. to 150° C.).

As used herein, the term "molecular weight" or "GPC" is measured by gel permeation chromatography of the analyte polyol (GPC) against polyether polyol or polyglycol (e.g., PEG) standards, unless otherwise specified. means the result of

As used herein, the term "hard segment" of a polyurethane reaction product or raw material derived from a thermosetting reaction mixture includes any diol, glycol, diglycol, diamine, triamine or polyamine, diisocyanate, tri It refers to isocyanates, or that portion of the indicated reaction mixture containing these reaction products. Thus, "hard segment" excludes polyethers or polyglycols with 3 or more ether groups, such as polytetramethylene glycol or polypropylene glycol.

As used herein, the term "PPG" refers to either poly(propylene glycol), ethylene oxide (EO) initiated PPG and (di)ethylene glycol extended PPG.

As used herein, the term "polyisocyanate" means any isocyanate group-containing molecule having three or more isocyanate groups, including blocked isocyanate groups.

As used herein, the term "polyisocyanate prepolymer" refers to excess diisocyanate or It means any isocyanate group-containing molecule that is a reaction product of a polyisocyanate.

As used herein, the term "polyurethane" refers to polymerization products derived from difunctional or multifunctional isocyanates, such as polyether ureas, polyisocyanurates, polyurethanes, polyureas, polyurethane ureas, these It refers to copolymers and mixtures thereof.

As used herein, the term "reactive mixture" refers to any non-reactive additive such as microelements or modulus or flexural stiffness enhancing additives such as boron nitride or poly(methacrylic acid) or polymeric polyacids such as salts thereof.

As used herein, the term "SG" or "specific gravity" refers to the weight/volume ratio of a rectangle cut from a polishing pad or layer according to the present invention.

As used herein, the term “Shore D hardness” is the 2 second hardness of a given material measured according to ASTM D2240-15 (2015), “Standard Test Method for Rubber Property—Durometer Hardness.” be. Hardness was measured with a Rex Hybrid hardness tester (Rex Gauge Company, Inc., Buffalo Grove, Ill.) equipped with a D probe. Six samples were stacked and shuffled between hardness measurements, and each pad tested was tested and used the method outlined in ASTM D2240-15 (2015) to improve hardness test reproducibility. It was conditioned by placing it in 50 percent relative humidity at 23° C. for 5 days before washing. In the present invention, the Shore D hardness of the polyurethane reaction product of the polishing layer or pad includes the Shore D hardness of that reaction product.

As used herein, the term "solids" refers to any material that remains in the polyurethane reaction product of the present invention. Solids therefore include reactive and non-volatile additives that do not volatilize upon curing. Solids exclude water, ammonia and volatile solvents.

As used herein, the term "step height" refers to the maximum film height difference between high and low regions of a feature to be polished within a three-dimensional semiconductor or memory substrate.

As used herein, the term "stoichiometry" of a reaction mixture refers to the molar equivalent ratio of (free OH groups + free _NH2 groups) to free NCO groups in the reaction mixture.

As used herein, unless otherwise specified, the term "substantially water-free" means that no water has been added to a given composition and that the materials entering the composition do not contain water. means not added. A "substantially water-free" reaction mixture may contain water present in the feedstocks in the range of 50-2000 ppm, or preferably 50-1000 ppm, or the reaction water produced in the condensation reaction, or The reaction mixture may contain vapors from the ambient moisture in which it is used.

As used herein, the term "use conditions" means the temperature and pressure at which one performs CMP polishing of a substrate or at which polishing occurs.

As used herein, unless otherwise indicated, the term "viscosity" is measured using a rheometer set to an oscillatory shear rate sweep of 0.1-100 rad/sec on a 50 mm parallel plate geometry with a gap of 100 μm. refers to the viscosity of a given material in neat form (100%) at a given temperature.

As used herein, unless otherwise specified, the terms "number average molecular weight" or "Mn" and "weight average molecular weight" or "Mw" are used for isocratic pumps, autosamplers (injection volume (50 μl), and a series of four PL-Gel™ (7 mm x 30 cm x 5 μm) columns each packed with polystyrene divinylbenzene (PS/DVB) gel in the order of 50, 100, 500 and then 1000 Å pore size. Against standards calibrated from polyol mixtures of polyethylene glycol and polypropylene glycol (1.5 wt% in THF) as standards using a 1100 High Pressure Liquid Chromatogram (HPLC) (Agilent (Santa Clara, Calif.)). Means values measured by gel permeation chromatography (GPC) at room temperature For polyisocyanate prepolymers, the isocyanate functional (N=C=O) groups of the isocyanate sample are from a dry methanol/THF solution. It was converted to the unreactive methyl carbamate using methanol.

As used herein, unless otherwise specified, the term "wt % NCO" refers to the amount of unreacted or free isocyanate groups in a given polyisocyanate prepolymer composition.

As used herein, the term "wt%" refers to percent by weight.

According to the present invention, the chemical mechanical (CMP) polishing pad comprises 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA) or 4,4'-methylene-bis-o-( 2-chloroaniline) (MbOCA) and a polyisocyanate prepolymer made from a polytetramethylene ether glycol (PTMEG) polyol, polypropylene glycol (PPG), or a polyol blend of PTMEG and PPG. has an upper polished surface containing the reaction product of the reaction mixture with Abrasive layers according to the present invention exhibit an advantageous shear storage modulus, measured as G′, and a low damping component in the relevant abrasive temperature regime (i.e., shear dynamic mechanical analysis (DMA), ASTM D5279-08 (2008) Hold the measured G''/G') (0.06-0.13). The unfilled polishing layer material of the present invention also has a high (>400 MPa) tensile modulus. High shear storage modulus and low damping coefficient CMP polishing layers to achieve high removal rates and excellent long length scale planarization required for three-dimensional semiconductor or memory substrates such as non-volatile flash memory (3D NAND) substrates enable In long length scale planarization, the CMP polishing layer of the present invention polishes a three-dimensional semiconductor or memory substrate having at least one low region of 1 mm or greater, such as 1-5 mm in width.

The CMP polishing layer of the CMP polishing pad of the present invention is a porous pad material that has a significantly higher modulus of elasticity and high bending stiffness at relevant temperatures. These properties are attributed to 4,4'-methylene-bis as a curing agent or as a diamine curing agent mixture of at least 30% by weight, or preferably at least 40% by weight, used in the thermosetting reaction mixture of the present invention. Realized by using (3-chloro-2,6-diethylaniline) (MCDEA). The addition of MCDEA to the curative mixture increases the elastic modulus (shear storage modulus) and improves long length flattening by retaining sufficient tan δ (damping component) at service conditions. For a given porosity, the CMP polished layer exhibits improved bending stiffness with increased modulus, which contributes to improved planarization capabilities at longer length scales (>3 mm). do. In addition, a higher modulus at the relevant substrate surface polishing temperature typically corresponds to a higher removal rate (RR). A higher tan δ or damping component can also improve flattening when compared to bending stiffness, but to a greater extent at shorter length scales (<1 mm). It is possible that in intermediate situations (1-5 mm) both parameters contribute to the planarization ability and that tan δ can be smaller in the shorter length scale situations. The CMP polishing temperature or conditions may not overlap with the temperature of a given material property measurement, because the measured platen temperature may not accurately reflect the temperature fluctuations within the polishing layer. Yes, and also because the polishing layer material is subjected to variable strain rates during the polishing operation.

The chemical mechanical polishing pad of the present invention comprises a polishing layer that is a homogeneous dispersion of microelements in porous polyurethane or homogeneous polyurethane. Homogeneity is important to achieving consistent polishing pad performance, especially when manufacturing multiple polishing pads using a single casting. Therefore, the reaction mixture of the present invention is chosen such that the resulting pad morphology is stable and easily reproducible. For example, it is often important to control additives such as antioxidants and impurities such as water for consistent manufacturing. Since water reacts with isocyanates to form gaseous carbon dioxide and generally weaker reaction products compared to urethanes, the concentration of water reduces the carbon dioxide bubbles that form pores within the polymer matrix. concentration as well as the overall consistency of the polyurethane reaction product. Reaction of the isocyanate with extraneous water also reduces the isocyanate available for reaction with the chain extender, thus altering the stoichiometry along with the level of crosslinking (if excess isocyanate groups are present). , tends to lower the resulting polymer molecular weight.

The porosity of the CMP polishing layer of the present invention can range from 0-53%, or preferably 8-40%, such as 12-25%. The polishing layer is more easily conditioned at higher porosity, but provides better stiffness and long length scale planarization at lower porosity.

To ensure homogeneity and good molding results, and to completely fill the mold, the reaction mixture of the invention should be well dispersed.

According to the invention, the reaction mixture comprises on the one hand at least an aromatic diisocyanate, for example toluenediisocyanate, and a polyisocyanate prepolymer prepared from a polyol component, and on the other hand a 4,4′- methylenebis(3-chloro-2,6-diethylaniline) (MCDEA), or MCDEA and 4,4'-methylene-bis-o-(2-chloroaniline) (MbOCA).

The polyurethane polymer material or reaction product is preferably, on the one hand, polytetramethylene ether glycol (PTMEG), polypropylene glycol (PPG), or polyols of PTMEG blended with PPG and toluene diisocyanate ( TDI) from polyisocyanate prepolymer reaction products of aromatic diisocyanates.

Aromatic diisocyanates or aromatic and cycloaliphatic diisocyanates are partially reacted with the polyol blend to form a polyisocyanate prepolymer before forming the final polymer matrix.

Polyisocyanate prepolymers may further be combined with methylene diphenyl diisocyanate (MDI), or diol or polyether extended MDI, or additionally reaction products of aromatic diisocyanates, polyols and MDI or extended MDI. The MDI is from 0.05 to 20% by weight, or such as up to 15% by weight, or such as, for example, 0.1%, based on the total weight of the aromatic diisocyanate used to prepare the polyisocyanate prepolymer. It is present in an amount of ˜12% by weight.

Polyisocyanate prepolymers may further be combined with methylene bis-cyclohexyl diisocyanate (H ₁₂ MDI), or diol or polyether extended H ₁₂ -MDI, or additionally aromatic diisocyanates, polyols and H ₁₂ -MDI or the product of extended H ₁₂ -MDI, where H ₁₂ -MDI is from 0.05 to 60, based on the total weight of aromatic and cycloaliphatic diisocyanates used to prepare the polyisocyanate prepolymer. %, or such as up to 53% by weight, or such as from 0.1 to 53% by weight. The combination may also be from 0.05 to 20% by weight, or such as up to 15% by weight, or such as by 0.1%, based on the total weight of the aromatic diisocyanates used to prepare the polyisocyanate prepolymer. May be combined or reacted with ~12 wt% MDI.

For clarity, in the case of diol or polyether extended MDI or H ₁₂ -MDI, the weight of MDI or H ₁₂ -MDI refers to the weight of MDI or H ₁₂ -MDI itself in the extended MDI or H ₁₂ -MDI. considered.

In this specification, formulations are expressed in weight percent unless otherwise specified.

The polyisocyanate prepolymer of the present invention has a total of 30 to 66 weight percent, or preferably 45 to 62 weight percent, based on the total weight of the aromatic diisocyanate and the reactants used to prepare the prepolymer. 43-62% by weight of the polyol blend (PPG and PTMEG), such as less than the reaction product of the mixture. The remaining portion of the reaction mixture contains the curing agent.

The polishing layer of the present invention is formed from a reaction mixture of a polyisocyanate prepolymer and a curing agent, the amount of curing agent being 23-33% by weight, or preferably 24-30%, based on the total weight of the reaction mixture. % range by weight.

A suitable polyisocyanate prepolymer preferably contains toluene diisocyanate (TDI) as partially reacted monomer, preferably in an amount of 16 to 46% by weight, or preferably greater than 20 to 45% by weight. is produced from a mixture of As used herein, TDI monomer or partially reacted monomer refers to the weight percent TDI monomer prior to curing the polyurethane or TDI monomer that has reacted into the prepolymer, and other Contains no reactants. Optionally, the TDI portion of the mixture may also contain some aliphatic isocyanates. Preferably, the diisocyanate component contains less than 15 wt% aliphatic isocyanates, more preferably less than 12 wt% aliphatic isocyanates. Preferably, the mixture contains only impurity levels of aliphatic isocyanates. For clarity, cycloaliphatic diisocyanates are not considered aliphatic isocyanates.

Examples of available PTMEG containing polyols are: Terathane™ 2900, 2000, 1800, 1400, 1000, 650 and 250 (from Invista, Wichita, Kans.); Polymeg™ 2900, 2000 , 1000, 650 from Lyondell Chemicals, Limerick, PA; PolyTHF™ 650, 1000, 2000 from BASF Corporation, Florham Park, NJ. Examples of available PPG containing polyols are: Arcol™ PPG-425, 725, 1000, 1025, 2000, 2025, 3025 and 4000 from Covestro (Pittsburgh, PA); ) 1010L, 2000L, and P400 (from Dow, Midland, Mich.); Desmophen™ 1110BD or Acclaim™ Polyol 12200, 8200, 6300, 4200, 2200 (each from Covestro).

Examples of commercially available PPG-containing isocyanate-terminated urethane prepolymers include Adiprene™ prepolymers (Chemtura) (LFG 963A, LFG 964A, LFG 740D, etc.); )) (such as 7000 AP, 8000 AP, 6500 DP, 9500 APLF, 7501, or DPLF). Examples of suitable PPG-based prepolymers include Adiprene™ prepolymers LFG740D and LFG963A.

Catalysts can be used to enhance the reactivity of polyols with diisocyanates or polyisocyanates to prepare polyisocyanate prepolymers. Suitable catalysts include, for example, oleic acid, azelaic acid, dibutyltin dilaurate, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tertiary amine catalysts such as Dabco TMR, and Including mixtures of the above.

Suitable polyisocyanate prepolymers of the invention have viscosities in neat form at 110° C. of up to 10,000 mPa.s, or preferably from 20 to 5,000 mPa.s.

Examples of suitable commercially available PTMEG-containing isocyanate-terminated urethane prepolymers include Imuthane™ prepolymers (available from COIM USA, Inc. of West Deptford, NJ) (PET-80A, PET-85A, PET -90A, PET-93A, PET-95A, PET-60D, PET-70D, or PET-75D); Adiprene™ prepolymers (Chemtura (Philadelphia, PA)) (e.g., LF 800A, LF 900A, LF) 910A, LF 930A, LF 931A, LF 939A, LF 950A, LF 952A, LF 600D, LF 601D, LF 650D, LF 667, LF 700D, LF750D, LF751D, LF752D, LF753D or L325); Andur™ prepolymers (Anderson Development Company (Adrian, MI)) (such as 70APLF, 80APLF, 85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, or 75APLF).

Additionally, the polyisocyanate prepolymers of the present invention can be low free aromatic isocyanate prepolymers having less than 0.1 wt. It has a consistent prepolymer molecular weight distribution. "Low free aromatic isocyanate" prepolymers with improved prepolymer molecular weight consistency and low free isocyanate monomer content facilitate a more regular polymer structure, leading to improved polishing pad consistency contribute.

Preferably, the polyurethane used in forming the polishing layer of the chemical mechanical polishing pad of the present invention is a low free isocyanate terminated urethane having a free toluene diisocyanate (TDI) monomer content of less than 0.1 weight percent. .

Additives such as antioxidants and impurities such as water are often added to ensure that the resulting pad morphology is stable and easily reproducible, e.g., for consistent manufacturing. is important to control. For example, since water reacts with isocyanate to produce gaseous carbon dioxide, the concentration of water can affect the concentration of carbon dioxide bubbles that form pores within the polymer matrix. The reaction of isocyanate with extraneous water also reduces the isocyanate available for reaction with polyamines, thus reducing OH or _NH2 to NCO groups along with the level of cross-linking (if excess isocyanate groups are present). The molar ratio of groups and the molecular weight of the resulting polymer are varied.

In the reaction mixture of the present invention, the stoichiometric ratio of total amine ( _NH2 ) groups and total hydroxyl (OH) groups in the reaction mixture to total unreacted isocyanate (NCO) groups in the reaction mixture is It ranges from 0.85:1 to 1.2:1, or preferably from 1.0:1 to 1.1:1.

The reaction mixture of the present invention has no added organic solvent.

Preferably, the reaction mixtures of the present invention are "substantially free of water" (less than 2,000 ppm) based on the total weight of the reaction mixture.

In the method of making the polishing layer of the present invention, the method comprises providing the polyisocyanate prepolymer of the present invention at a temperature of 45-65°C; providing curatives to form a thermosetting reaction mixture of the polyisocyanate prepolymer and, if desired, the microelement material as one component and the curative as another component. , preheating the mold to 60-100° C., or preferably 65-95° C., filling the mold with the reaction mixture and heating the reaction mixture at a temperature of 80-120° C. for 4-24 hours, or preferably Heat curing for 6-16 hours to form a molded polyurethane reaction product.

The method of forming the abrasive layer of the present invention involves skiving or slicing a molded polyurethane reaction product to form a layer having a thickness of 0.5 to 10 mm, or preferably 1 to 3 mm. further including

The method of making the polishing layer of the present invention allows for the production of low porosity pads from a reaction mixture that provides a large exotherm and cures unusually fast to form a hard molded polyurethane reaction product. Cooling of the polyisocyanate prepolymer component and preheating of the mold prevents popping of the mold or cake (where the hardened or cast material releases from the base and cannot be skived or sliced to form a polishing layer. )prevent. In addition, the method of manufacturing the CMP polishing pad of the present invention avoids non-homogeneous secondary expansion of the microelements and limits the variation of SG within the resulting mold or cake, thereby reducing post-skiving or slicing improve the yield of the abrasive layer from the mold or cake.

The chemical mechanical polishing pads of the present invention may comprise a polyurethane reaction product polishing layer alone or a polishing layer laminated onto a subpad or underlayer. In the case of the polishing pads or laminate pads of the present invention, the polishing layer of the polishing pad is useful in both porous and non-porous or unfilled configurations. The finished polishing pad or polishing layer (in laminated pads), whether porous or non-porous, preferably has a weight of 0.7 to 1.20 g/cm ³ or more preferably 0.9 It has a density of ˜1.08 g/cm ³ . Porosity can be increased by gas dissolution, blowing agents, mechanical foaming and the introduction of hollow microspheres. Polishing pad density is measured according to ASTM D1622-08 (2008). Density is closely correlated within 1-2% of specific gravity.

The porosity within the polishing layer of the present invention typically has an average diameter of 2-50 μm. Most preferably, the porosity results from hollow polymer particles having a spherical shape. Preferably, the hollow polymer particles have a weight average diameter of 2-40 μm. As used herein, weight average diameter refers to the diameter of hollow polymer particles prior to casting, and the particles may have a spherical or non-spherical shape. Most preferably, the hollow polymer particles have a weight average diameter of 10-30 μm.

The polishing layer of the chemical mechanical polishing pad of the present invention optionally further comprises microelements, preferably evenly distributed throughout the polishing layer. Such microelements, especially hollow spheres, can expand during casting. Microelements include trapped air bubbles, hollow core polymeric materials such as polymeric microspheres, liquid filled hollow core polymeric materials such as fluid filled polymeric microspheres, water soluble materials, insoluble phase materials (e.g. mineral oil), and abrasive fillers. , boron nitride, and the like. Preferably, the microelements are selected from trapped cells and hollow core polymeric materials uniformly distributed throughout the polishing layer. The microelements have a weight average diameter of less than 100 μm (preferably 5-50 μm). More preferably, the plurality of microelements comprises polymeric microspheres (eg, Expancel™ beads from Akzo Nobel, Amsterdam, Netherlands) having shell walls of either polyacrylonitrile or polyacrylonitrile copolymer.

According to the present invention, the microelements are incorporated into the polishing layer at 0.4-5.5 wt% porogen, or preferably 0.75-5.0 wt%.

The polyurethane reaction product of the polishing layer of the chemical mechanical polishing pad of the present invention exhibits a Shore D hardness of 50-90 measured according to ASTM D2240-15 (2015).

Preferably, the polishing layer used in the chemical mechanical polishing pads of the present invention is 500 to 3750 microns (20 to 150 mils), or more preferably 750 to 3150 microns (30 to 125 mils), or even more preferably , 1000-3000 microns (40-120 mils), or most preferably 1250-2500 microns (50-100 mils).

The chemical mechanical polishing pad of the present invention optionally further comprises at least one other layer compatible with the polishing layer. Preferably, the chemical mechanical polishing pad optionally further comprises a compressible subpad or base layer adhered to the polishing layer. A compressible base layer preferably improves the conformability of the polishing layer to the surface of the substrate being polished.

The polishing layer of the chemical mechanical polishing pad of the present invention has a polishing surface adapted for polishing a substrate. Preferably, the polishing surface has a macrotexture selected from at least one of perforations and grooves. Perforations may extend from the polishing surface through part or all of the thickness of the polishing layer.

Preferably, the grooves are arranged in the polishing surface such that at least one groove passes through the surface of the substrate being polished as the chemical mechanical polishing pad rotates during polishing.

Preferably, the polishing surface has a macrotexture comprising at least one groove selected from the group consisting of curved grooves, linear grooves, perforations and combinations thereof.

Preferably, the polishing layer of the chemical mechanical polishing pad of the present invention has a polishing surface adapted for polishing a substrate, the polishing surface having a macrotexture including a groove pattern formed therein. Preferably, the groove pattern includes a plurality of grooves. More preferably, the groove pattern includes concentric grooves (which can be circular or spiral), curvilinear grooves, cross-hatch grooves (eg, arranged as an XY grid across the pad surface), other regular grooves. Groove designs such as those selected from the group consisting of designs (eg, hexagonal, triangular), tire tread type patterns, irregular designs (eg, fractal patterns), and combinations thereof. More preferably, the groove design is selected from the group consisting of random grooves, concentric grooves, spiral grooves, crosshatch grooves, XY lattice grooves, hexagonal grooves, triangular grooves, fractal grooves and combinations thereof. be done. Most preferably, the polishing surface has a spiral groove pattern formed therein. The groove cross-section is preferably selected from rectangular with straight sidewalls, or the groove cross-section can be "V"-shaped, "U"-shaped, serrated, and combinations thereof.

A method of making the chemical mechanical polishing pad of the present invention comprises providing a mold; casting the reaction mixture of the present invention into the mold; and reacting the combination within the mold to form a hardened cake. The abrasive layer may be derived from the cured cake. Preferably, the hardened cake is skived to obtain multiple abrasive layers from a single hardened cake. Optionally, the method further comprises heating the hardened cake to facilitate the skiving operation. Preferably, the hardened cake is heated using infrared heat lamps during the skiving operation and the hardened cake is skived into a plurality of abrasive layers.

Another method of making the chemical mechanical polishing pad of the present invention is by mixing the hardener in fluid form, preferably as a melt, with the polyisocyanate prepolymer containing any microelements in a vortex mixer. A thermosetting reaction mixture is formed, and the mixture is then sifted using a drawdown bar or doctor blade, e.g. inch) sheets and hardened drawdown techniques. The microelements are mixed into the polyisocyanate prepolymer prior to adding the curing agent to the thermosetting reaction mixture. Curing is accomplished by heating the oven from ambient temperature to a set point temperature of 80-120° C., e.g., 104° C., holding at the set point temperature, e.g., 4-24 hours, and then reducing the oven set point temperature to room temperature (21° C. ), for example, a 2 hour ramp down. The cured sheet may be surface finished, such as using a lathe.

In a method of manufacturing a polishing pad according to the present invention, chemical mechanical polishing pads can be provided having groove patterns cut into their polishing surface for promoting slurry flow and removing debris from the pad-wafer interface. Such grooves can be cut into the polishing surface of the polishing pad using a lathe or by a CNC milling machine.

In the method of using the polishing pad of the present invention, the polishing surface of the CMP polishing pad can be conditioned. Pad surface "conditioning" or "dressing" is extremely important in maintaining a consistent polishing surface for consistent polishing performance. Over time, the polishing surface of the polishing pad wears away, smoothing the microtexture of the polishing surface (a phenomenon called "glazing"). Polishing pad conditioning is typically accomplished by mechanically abrading the polishing surface with a conditioning disc. Conditioning discs have a rough conditioning surface, typically consisting of embedded diamond points. The conditioning process abrades and burrows the pad material, cutting microgrooves into the pad surface while recreating the abrasive texture.

Conditioning of the polishing pad can be accomplished by applying the conditioning disk either during intermittent interruptions of the CMP process (“ex sits”) when polishing is paused, or while the CMP process is in progress (“in situ”). Including contact with an abrasive surface. Typically, the conditioning disc rotates in a fixed position relative to the polishing pad's rotational axis and passes through an annular conditioning region as the polishing pad rotates.

The chemical mechanical polishing pad of the present invention can be used to polish substrates selected from at least one of memory substrates and semiconductor substrates.

A three-dimensional semiconductor substrate or memory substrate may have a feature scale or die scale between features that need to be planarized, 1-50 mm, preferably 1-20 mm.

Preferably, the method of polishing a substrate of the present invention provides a substrate selected from at least one of a three-dimensional semiconductor substrate, such as a non-volatile flash memory (3D NAND) substrate, or a memory substrate; providing a chemical mechanical polishing pad; causing dynamic contact between the polishing surface of the polishing layer and the substrate to polish the surface of the substrate; and conditioning the polishing surface with an abrasive conditioner. In the method of the present invention, providing dynamic contact includes polishing with a Down Force (DF) of 103-550 hPa (1.5-8 psi), or preferably 206-483 hPa (3-7 psi). . DF ranges from greater than 200 hPa to 550 hPa, preferably from 275 hPa to 475 HPa for use with slurries having lower abrasive content in the range of 0.5-2 wt% abrasive (e.g. silica) solids. can be. DF is also 103-344 hPa (1.5-5 psi) for use with slurries having a higher abrasive content of 2-6 wt % or preferably 2.5-5.5 wt % Or, preferably, it can be lower, such as 137-344 hPa (2-5 psi).

Examples: The invention will now be described in detail in the following non-limiting examples.

Unless otherwise noted, all temperatures are room temperature (21-23° C.) and all pressures are atmospheric (approximately 760 mm Hg or 101 kPa).
The following ingredients were used in the examples, regardless of the other ingredients disclosed below:
MONDUR™ Grade II TDI: toluene diisocyanate (Covestro (Pittsburgh, PA));
TERATHANE™ 1000: 1000 Mw polytetramethylene ether glycol (Invista (Wichita, KS));
Adiprene™ LF 750D: low free TDI (<max 0.5%) prepolymer from PTMEG (8.75-9.05 wt% NCO, Mn = 760 Da; Mw = 870 Da (Chemtura (Philadelphia, PA)) ;
Adiprene™ L 325: TDI-terminated liquid urethane prepolymer from PTMEG (8.95-9.25 wt% NCO, Mn=990 Da; Mw=1250 Da, Chemtura);
Prepolymer A: H from PTMEG and TDI (about _10.5 % wt.% NCO) with about 64% wt. ₁₂ MDI terminated liquid urethane quasi-prepolymer; Mn about 760 Da; Mw about 870 Da;
Adiprene™ LFG 740D: low free TDI (<max 0.5%), TDI terminated liquid urethane prepolymer derived from polyol containing PPG; (8.65-9.05 wt% NCO, Chemtura);
MDI Prepolymer: Linear isocyanate-terminated urethane prepolymer with about 23 wt% NCO content and equivalent weight of 182 derived from methylene diphenyl diisocyanate (MDI) and small molecule dipropylene glycol (DPG) and tripropylene glycol (TPG) . 100% by weight of this MDI prepolymer is treated as hard segment;
Lonzacure™ MCDEA: 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), (Lonza Ltd. (Switzerland));
Expancel™ 551 DE 40 d42 beads: Fluid-filled polymeric microspheres (Akzo Nobel (Arnhem, NL)) with a nominal diameter of 40 μm and a true density of 42 g/l;
Expancel™ 461 DE 20 d70 beads: Fluid-filled polymeric microspheres (Akzo Nobel) with a nominal diameter of 20 μm and a true density of 70 g/l; and
Expancel™ 031 DU 40 beads: dry, unexpanded polymeric microspheres (Akzo Nobel) with a nominal diameter of 13 μm and a true density of about 1000 g/l.
The following other abbreviations are used in the examples below:
TDI: toluene diisocyanate (2,4 isomer about 80%, 2,6 isomer about 20%); MbOCA: 4,4'-methylenebis(2-chloroaniline).

Example 1: Synthesis of CMP polishing layers and pads: A 34'' diameter polytetrafluoroethylene (PTFE) with a flat bottom for making moldings for use in making polishing pads or polishing layers. Coating) A polishing layer comprising the reaction product of the reaction mixture formulations set forth in Table 1 below was formed by casting the formulation into a circular mold. To produce the formulation, the indicated polyisocyanate prepolymer was heated to 52° C. to ensure sufficient flow and premixed in combination with the indicated Expancel™ microelement(s). A mixed component was produced, which was then mixed with the curative as a separate component using a high shear mixing head. After exiting the mixing head, the formulation was dispensed into the molds over 2-5 minutes to give a total casting thickness of 4-10 cm and allowed to gel for 15 minutes before placing the molds in the curing oven. The mold was then cured in a curing oven using the following cycle: 30 minute ramp from ambient temperature to 104°C set point, then hold at 104°C for 15.5 hours, then from 104°C. 2 hour ramp to 21°C.

To cast the reaction mixture formulation as a cake, cast the pad using a prepolymer line heat exchanger that reduces the prepolymer casting temperature to the indicated temperature of 52°C to 27°C (80°F) and the mold to 93°C. preheated to This makes it possible to control high heat generation and reduce variations within the mold.

Porosity is proportional to microsphere loading and inversely proportional to SG.

The cured polyurethane cake was then removed from the mold and skived (cut using a stationary blade) into approximately 30 separate 2.0 mm (80 mil) thick sheets at a temperature of 70-90°C. Skiving started from the top of each cake. All incomplete sheets were discarded.

The non-grooved polishing layer materials according to each example were analyzed to determine their physical properties. Reported pad density data were measured according to ASTM D1622-08 (2008), reported Shore D hardness data were measured according to ASTM D2240-15 (2015), and reported modulus and elongation at break data were measured according to ASTM D412. - Note that it was measured according to 6a (2006). Test results are shown in Tables 2, 3, 4, 5 and 6 below.

Test Methods: The following methods were used to test the polishing pads, including the property tests indicated above:
Polishing: A chemical mechanical polishing pad was constructed using a polishing layer. These polishing layers were then machine grooved to provide a polishing surface groove pattern containing perforations or multiple concentric grooves having the following dimensions: Suba™ 400 Urethane for Examples 2 and 3; A perforated pad with polyester mat subpads (Nitta Haas, JP) of size 0.76 mm (30 mil) deep, 0.51 mm (20 mil) wide and 3.05 mm (120 mil) pitch was used in Example 4. 1010 grooves.

The polishing layer was then laminated to a foam subpad layer (SUBA IV available from Rohm and Haas Electronic Materials CMP Inc.). A double-sided pressure sensitive adhesive film was used to attach the resulting pad to the polishing platen of the polishing apparatus shown.

The indicated substrates were polished with the indicated pads using the CMP polishing platform indicated below. The indicated polishing media used in polishing experiments (eg, CES333F ceria slurry, Asahi Glass Company, JP). Unless otherwise stated (as platen rpm (PS)/carrier rpm (CS)), the polishing conditions used in all polishing experiments were platen speed 93 rpm; carrier speed 87 rpm; It contained Force (DF). An AM02BSL8031C1-PM (AK45) diamond conditioning disc (Saesol Diamond Ind. Co., Ltd.) was used to condition the chemical mechanical polishing pad. Each chemical mechanical polishing pad was run down with conditioner for 40 minutes using 3.2 kg (7 lbs) of downforce. The polishing pad was further conditioned in situ using 3.2 kg (7 lbs) downforce. Removal rate (RR) was determined by measuring film thickness before and after polishing using an FX200 metrology tool (KLA-Tencor, Milpitas, Calif.) using a 49-point spiral scan excluding 3 mm of the edge.

Step Height: Low area and feature level measurement difference measured by optical interference using RE-3200 Ellipsometric Film Thickness Measurement System (Screen Holdings Co. Ltd., JP). Desirably, the residual step height is as low as possible.

Example 2: Ceria slurry polishing on wafer substrates: In Table 2 below, a FREX™ 300 polishing platform (Ebara, Tokyo, JP) was used with a downforce of 410 hPa (6 psi) and a Hitachi HS8005 ceria slurry (Hitachi , Corp., JP) at a final solids content of 0.5 wt% (1:9 dilution), 240 nm (d50) and a pH of about 8.4. did. The substrate was a tetraethoxyorthosilicate (TEOS) oxide film on a patterned polysilicon wafer. Prior to polishing, the CMP polishing pad marked with a DF of 100 N was subjected to 30 seconds of ex situ conditioning using a Kinik EP1AG-150730-NC™ conditioning disc (Kinik (Taipei, TW)).

As shown in Table 2 above, CMP polishing pads H and I of the present invention provided dramatically higher removal rates than those of the closest technology in CMP polishing pads A and B.

Example 3: Ceria Slurry Polishing on Feature Substrates: In Table 3 below, Hitachi HS8005™ ceria slurry was 0.5 wt% final solids (1:9 dilution), 240 nm (d50) and pH about 8.0 4, the indicated CMP polishing pads were tested at a DF of 500 hPa (7.25 psi) in the polish defined in Example 2 above (excluding platen/carrier speeds (100/107 rpm)). The substrate was a tetraethoxyorthosilicate (TEOS) oxide film on a patterned polysilicon wafer.

As shown in Table 3 above, the preferred CMP polishing pad D of the invention is CMP polishing pad E (made from the same polyisocyanate prepolymer of the same stoichiometry but without the curing agent of the invention). has a dramatically higher removal rate than that of the closest technology in

Example 4: Polishing with Various Removal Rates: In Table 4 below, an Ebara Reflexion polisher (300mm, Ebara) was used to polish a ceria slurry (pH 3.5 and average particle size 150nm) at 6wt% solids. Using the indicated carrier/platen velocity and the indicated downforce (DF), the indicated CMP polishing pad was tested in the polish defined above. The substrate was a tetraethoxyorthosilicate (TEOS) oxide film on a patterned polysilicon wafer.

As shown in Table 4 above, CMP Polishing Pads D and G of the present invention were compared to CMP Polishing Pad A (not using the curing agent of the present invention or made with the stoichiometry of the present invention). gave a higher removal rate than that of the technique in Pad G made from MCDEA, MbOCA curative blend gave the best results. Step height data taken at 172 hPa (2.5 psi DF) show that the inventive pad improves long length scale flatness. The RR data show that the improvement of the inventive pad over the comparative polishing pad increases with increasing DF and increasing platen/carrier velocity.

Example 5: Copper and Tungsten Metal Polishing: For polishing layer J using a combination of 2.91 wt% Expancel™ 461 DE 20 d70 and 1.7 wt% Expancel™ 031 DU 40 Polishing layers J1-J3 were constructed according to the reaction mixture formulations described in Table 1. Their properties are shown in Table 5 below. The inclusion of Expancel™ 031 DU 40 further increases pad porosity and reduces pad SG to about 0.63. Similarly, Polishing Layer A was prepared according to Table 1 for comparison. However, it was modified to include a combination of 2.91 wt% Expancel™ 461 DE 20 d70 and 1.7 wt% Expancel™ 031 DU 40.

Chemical mechanical polishing pads, Pad J and Comparative Pad A were constructed using the corresponding polishing layers described above and tested for polishing copper or tungsten films on wafer substrates.

The polishing layer was mechanically grooved to provide a groove pattern on the polishing surface containing a plurality of concentric grooves having the following dimensions: 0.76 mm (30 mil) deep, 0.51 mm (20 mil) wide and 1 pitch. A 70 mil K7 groove and another 32 radial grooves 0.76 mm (30 mil) deep and 0.76 mm (30 mil) wide.

The polishing layer was then laminated to a foam subpad layer (SUBA IV available from Rohm and Haas Electronic Materials CMP Inc.). A double-sided pressure sensitive adhesive film was used to attach the resulting pad to a polishing platen. The final pad has a diameter of 775 mm (30.5'').

A CMP polishing platform, Reflexion® LK from Applied Materials, Santa Clara, Calif., was used to polish 300 mm wafers. Polishing conditions included a platen speed of 93 rpm; a carrier speed of 87 rpm; and a polishing media flow rate of 300 mL/min.

CSL9044 bulk copper slurry (Fujifilm Planar Solutions (Japan)) containing 1.5 wt % colloidal silica abrasive and 1 wt % H ₂ O ₂ at pH about 7 during use and pH 2-2. 5 were evaluated, including W2000™ bulk tungsten slurry (Cabot Microelectronics (Aurora, Ill.)) with 2 weight percent fumed silica abrasive and 2 weight percent H ₂ O ₂ . Each slurry was used to polish the following substrates:
・CSL9044C (copper polishing): Cu wafer (3 psi (20.7 kPa));
• W2000 (tungsten polish): W, TEOS, and SiN sheet wafers (2 psi (13.8 kPa) and 4 psi (27.6 kPa)).

Conditioning disc AM02BSL8031C1-PM (AK-45™ disc, Saesol Diamond Ind. Co., Ltd, Gyeonggi-do (Korea)) was used for run-in and conditioning of the CMP polishing pad before polishing. Each new pad was broken in at 7 lbf (31 N) downforce for 30 minutes and an additional 5 minutes before slurry change. During polishing, 100% in situ conditioning was used at 5 lbf (22 N) for copper polishing and 30 seconds of ex situ conditioning at 7 lbf (31 N) was used for tungsten polishing. Ten dummy wafers were polished, followed by three wafers to determine the polish removal rate and other polishing properties.

Removal rates were determined by measuring the film thickness before and after polishing using an FX200 metrology tool (KLA-Tencor, Milpitas, Calif.) using a 49-point spiral scan excluding 3 mm of the edge.

The removal rate (RR) polishing results are shown in Tables 6 and 7 below. The normalized results are set to either 100% or 1 where applicable for the comparative example.

% Non-Uniformity (%NU): %NU was determined by calculating the range of final film thickness after polishing. % NU polishing results are shown in Tables 6 and 7 below.

As shown in Tables 6 and 7 above, Pad J showed significant improvement over Comparative Pad A, especially at higher polishing temperatures.

Claims (10)

A chemical mechanical (CMP) polishing pad having a low attenuation component for polishing a substrate selected from at least one of memory and semiconductor substrates, the pad comprising 4,4′-methylenebis(3-chloro-2,6- diethylaniline) (MCDEA) or a mixture of MCDEA and MbOCA in a weight ratio of 3:7 to 1:0 of MCDEA to 4,4'-methylene-bis-o-(2-chloroaniline) (MbOCA) and a curing agent , having an unreacted isocyanate (NCO) concentration of 8.6 to 11 wt. mixtures with alicyclic diisocyanates up to 67 wt. a polyurethane reaction product of a thermosetting reaction mixture comprising a polyisocyanate prepolymer made from a polyol blend of PPG and a polishing layer adapted to polish said substrate, said polishing layer having a hollow core. microelements comprising polymeric material, wherein the polyurethane reaction product within the polishing layer has a Shore D hardness of 50-90 according to ASTM D2240-15 (2015), and wherein the polyurethane reaction product within the polishing layer. The article has a shear storage modulus (G′) at 65° C. of 70-500 MPa, and said abrasive layer has a damping component at 50° C. of 0.06-0.13 (shear dynamic mechanical analysis (DMA ), G''/G' measured by ASTM D5279-08 (2008)) , and a porosity of 47% to 53% . Claim 1, wherein the curing agent comprises a mixture of MCDEA and 4,4'-methylene-bis-o-(2-chloroaniline) (MbOCA) in a weight ratio of MCDEA to MbOCA of 4:6 to 1:0. CMP polishing pad as described. The aromatic diisocyanate, or mixtures thereof with cycloaliphatic diisocyanates, is toluene diisocyanate (TDI), methylene diphenyl diisocyanate up to 20% by weight based on the total weight of the aromatic diisocyanate 2. TDI mixed with (MDI), or a mixture of TDI and up to 67% by weight of _H12MDI based on the total weight of said aromatic and cycloaliphatic diisocyanates. CMP polishing pad. The polyisocyanate prepolymer has an unreacted isocyanate (NCO) concentration of 8.6 to 10.3% by weight of the polyisocyanate prepolymer and is used to form the polyisocyanate prepolymer. said polyol is selected from (i) PTMEG, (ii) PPG or (iii) a polyol blend of PTMEG and PPG in a ratio of PTMEG to PPG of 1:0 to 1:4 or 12:1 to 1:1 The CMP polishing pad of claim 1. The stoichiometry of the sum of the total number of moles of amine ( _NH2 ) groups and the total number of moles of hydroxyl (OH) groups in the reaction mixture versus the total number of moles of unreacted isocyanate (NCO) groups in the reaction mixture The CMP polishing pad of claim 1, wherein the ratio ranges from 0.90:1 to 1.20:1. 2. The CMP polishing pad of claim 1, wherein said polishing layer of said CMP polishing pad further comprises microelements selected from entrapped air bubbles , liquid-filled hollow core polymeric materials, and fillers. The polyurethane reaction product in the polishing layer has a Shore D hardness of 60-90 according to ASTM D2240-15 (2015) and a shear storage modulus (G') at 65°C of 125-500 MPa. The CMP polishing pad according to item 1. The CMP polishing pad of claim 1, wherein said polishing pad or polishing layer has a density of 0.55-1.17 g/cm ³ . The CMP polishing pad of claim 1, wherein said polishing layer comprises a polyurethane reaction product having 45-70% hard segments based on the total weight of said thermoset reaction mixture. providing a substrate selected from at least one of a three-dimensional semiconductor or memory substrate; providing the chemical mechanical (CMP) polishing pad of claim 1; providing an abrasive polishing medium; causing dynamic contact between the polishing surface of the polishing layer of the CMP polishing pad, the abrasive polishing medium, and the substrate to strike the surface of the substrate with a down force (DF) of 103 to 550 hPa (1.5 to 8 psi); A method of chemical mechanical (CMP) polishing a substrate, comprising polishing; and conditioning the polishing surface of the polishing pad with an abrasive conditioner.